@article{DAN_1986_289_2_a5,
     author = {S. M. Nikol'skii and P. I. Lizorkin},
     title = {Approximation of functions by spherical polynomials in the metric $L_p$},
     journal = {Doklady Akademii Nauk},
     pages = {285--289},
     publisher = {mathdoc},
     volume = {289},
     number = {2},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1986_289_2_a5/}
}